Generally, such a casing provides a housing which is open at at least one end into which the bundle of tubes constituting the heat exchanger can be slid like a drawer. The casing also provides ducting running across the housing for the heat exchanger such that air flowing in said ducting passes through the heat exchanger bundle to be heated or cooled therein.
Up to the present, heat exchangers have been fixed in their casings by suitable auxiliary means, e.g. by screws, cooperating with lugs projecting from a heat exchanger's water box and having holes through which screws or other suitable fasteners are passed. Such assembly is a lengthy, and hence expensive, operation.
Proposals have also been made to fix a heat exchanger in its housing by means of lugs which depend from its water box and which act as spring clips. However, in this case the lugs are fragile and are dangerously exposed until the heat exchanger has been fixed in its casing.
Preferred embodiments of the present invention simplify and facilitate fixing a heat exchanger in its housing in the casing. This is done at reduced cost and avoiding the drawbacks of the prior art.